Generally, the human body can generate heat from metabolic processes and/or physical activity. When heat generation exceeds heat loss, one may feel hot. Alternatively, when heat loss exceeds heat generation, one may feel cold. Thermal comfort may be perceived when heat generation and heat loss are substantially similar. Outdoor comfort can depend on a variety of factors that mediate heat loss. For example, heat loss can be mediated by air temperature, humidity, and/or wind speed.
Previous approaches to determining outdoor comfort may provide two-parameter indices, multi-parameter indices, indices based on empirical formulas, and/or indices based on physical models derived from first principles. In some cases, such approaches may rely only on atmospheric data. In some cases, such approaches may be applicable only in select temperature ranges. Further, previous approaches may not be personalized to particular individuals and may not adapt to the sorts of variations in physiology and/or psychology that individuals may experience in response to their changing environment.